Polymer surfaces such as the surfaces of polyethylene and polypropylene films are conventionally treated by corona discharge to enhance their printability and to increase the adhesion of inks or other coatings. It is believed that corona discharge results in surface oxidation resulting in a variety of oxygen containing groups, a large portion of which are hydroperoxy groups. Without further treatment, the hydroperoxy groups react further to give a surface containing hydroxyl, carbonyl, and carboxyl groups.
In accordance with this invention, the corona discharge treated film is immediately treated with a reducing agent to convert the hydroperoxy groups to hydroxy groups.